Original 1968 Z/28 spare tire?

[1967Z28]

You don't have to do any more forensics. The black on the backside of the wheel is clearly the original dipped factory black and the blue on the front of your untouched spare is clearly original. CRG has seen a fair number of examples of this and it is not a question "If" this was ever available. It is a fact that it was.

[Too Many Projects]

I can see the hint of black on the edges of the blue, the colors aren't all that contrasting to differentiate and with dip, that coating could be so thin as to be nearly transparent in one area and running with drips on the opposite side from hanging on a rack for the dipping process.
You've heard from one of the foremost authorities on Los Angeles built, first gen Camaros and especially Z28's. When Jon says there is no doubt, the discussion is over...